1. Field of the Invention
The present invention relates to flow restrictor valve operators and more particularly to an operating control for opening and closing the flow passageway through a restrictor valve.
2. Description of the Prior Art
Flow restrictor valves are usually provided with a pair or several discs intersecting its flow passageway. The discs usually have graduated slots or apertures mating and mismating to open and close the valve fluid passageway. One of the discs is angularly rotated relative to the other to permit a predetermined quantity of fluid to flow through the valve. The restrictor valve restrictive apertures are opened to full flow from a closed position by substantially 90.degree. angular rotation of one of the flow passageway intersecting discs. Heretofor remote controls for such restrictor valves have usually comprised a series of pivotally interconnected links operated by a prime mover for angular rotation of a portion of the valve containing one of the flow restrictor discs. A repeatable predetermined angle of rotation of a flow passageway opening disc is difficult to achieve by mechanical linkage controls or levers due in part to the necessary tolerance of connected components. Furthermore, full torque of the driving motor when operating linkage to move the valve opening components of a restrictor valve through an arc of 90.degree. cannot easily be utilized resulting in approximately only 70% of the driving motor torque being applied to the linkage due to the arc through which the connected lever must move. This reduced torque usually being applied to the valve in an effort to open the valve passageway from a closed position which ordinarily requires the greater torque.
This invention is distinctive over the pivoting lever type operators for controlling the setting of a restrictive valve by providing a pair of cooperating part-circular plates operatively connected with a restrictor valve and a driving motor which opens and closes the valve by a flexible strand entrained around cooperating arcs of the plates.